Re: [PATCH v2] Check the node argument passed to cpumask_of_node

[Jin Dongming <jin.dongming@np.css.fujitsu.com>]

Hi, David

This problem also happened when the CONFIG_DEBUG_PER_CPU_MAPS was used,
so how about modifying the code for it working well?

Best Regards,
Jin Dongming

David John wrote:
> Commit e0cd516 "PCI: derive nearby CPUs from device's instead of bus' NUMA information"
> causes an null pointer dereference when reading from the sysfs attributes local_cpu*
> on Intel machines with no ACPI NUMA proximity info, since dev->numa_node gets set to -1
> for all PCI devices, which then gets passed to cpumask_of_node.
> 
> Ensure that the node value is valid.
> 
> Signed-off-by: David John <davidjon@xenontk.org>
> 
> diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
> index c5087d7..1141a6e 100644
> --- a/arch/x86/include/asm/topology.h
> +++ b/arch/x86/include/asm/topology.h
> @@ -99,7 +99,8 @@ extern const struct cpumask *cpumask_of_node(int node);
>  /* Returns a pointer to the cpumask of CPUs on Node 'node'. */
>  static inline const struct cpumask *cpumask_of_node(int node)
>  {
> -	return node_to_cpumask_map[node];
> +	return (node < 0 || node >= nr_node_ids) ? cpu_online_mask :
> +						   node_to_cpumask_map[node];
>  }
>  #endif
>  
> --
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